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Plasma drivers and other unconventional designs

Blumlein 88

Blumlein 88

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Cosmik said:
Yes, but the very idea of high fidelity was invented by those boring old 'objectivists'. They have the copyright. :)

To this day, 'subjectivists' repetitively churn the technology that was invented by previous generations of 'objectivist' scientists and engineers. In effect, at the same time as saying that the originators of hi fi were wrong about fidelity to the signal, they pay homage to those same people when they use their vinyl/valve/passive clone systems.

And what are these "big problems"? If there are such problems, why do people ever get into audio? Doesn't a good audio system just sound incredible, which is why people get hooked on it? Yes, even vinyl, valves and passive speakers - created by scientists and engineers in an attempt to get as close as possible to the recording.
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Well that kind of thinking is why I want an original Rice and Kellogg electrostat complete with gold leaf coated pig intestines membrane. Driven by a 200 watt SET. It will sound great streaming some sweet tunes over it. I figure a little Armor All on the pig intestine will keep it from rotting like it did on them. We just needed a little modern chemistry to help.

Then again, Rice and Kellogg experimented with a plasma speaker before deciding it was impractical going for the electrostat instead. I wonder what the Plasma unit was like?
 
Blumlein 88 said:
Well that kind of thinking is why I want an original Rice and Kellogg electrostat complete with gold leaf coated pig intestines membrane. Driven by a 200 watt SET. It will sound great streaming some sweet tunes over it. I figure a little Armor All on the pig intestine will keep it from rotting like it did on them. We just needed a little modern chemistry to help.

Then again, Rice and Kellogg experimented with a plasma speaker before deciding it was impractical going for the electrostat instead. I wonder what the Plasma unit was like?
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Nelson Pass became seriously ill from the ozone generated by demoing his prototype plasma speaker at shows. It was quickly withdrawn from further development.

I seem to recall another plasma design back in the day that also quickly disappeared.

Not a viable idea for human consumption. But, the sound, as they say, was to die for, literally.
 
Fitzcaraldo215 said:
Nelson Pass became seriously ill from the ozone generated by demoing his prototype plasma speaker at shows. It was quickly withdrawn from further development.

I seem to recall another plasma design back in the day that also quickly disappeared.

Not a viable idea for human consumption. But, the sound, as they say, was to die for, literally.
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Just means the technology needs a little more development. Maybe a magnetic containment bottle for the plasma.

I seem to remember one good thing was these plasma speakers were very efficient.

I think the other one in mind was made by a French company. Same issue, they thought they had a way to keep ozone to tolerable levels, but it didn't work well enough.
 
Off-topic: Plasma drivers

There have been several "plasma" speakers and tweeters (Ionovac, anyone?) but the one I remember is the Hill Plasmatronics; think it is the only one I actually heard.

https://www.stereophile.com/content/hill-plasmatronics-type-1-loudspeaker

Gotta' love this comment from the review (ca. 1980):

"Considering the current chaotic state of the high-end" audio field, few listeners will get any real idea of what these speakers can and cannot do until digital program sources become more widely available."

I am an engineer so English, albeit my native tongue, is a foreign language... :)
 
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DonH56 said:
Off-topic: Plasma drivers

There have been several "plasma" speakers and tweeters (Ionovac, anyone?) but the one I remember is the Hill Plasmatronics; think it is the only one I actually heard.

https://www.stereophile.com/content/hill-plasmatronics-type-1-loudspeaker

I am an engineer so English, albeit my native tongue, is a foreign language... :)
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Don, I find your posts very intelligible but then I,too, am an engineer. Interesting article. It ignores the KISS principle, though . o_O
 
DonH56 said:
I am an engineer so English, albeit my native tongue, is a foreign language... :)
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Wombat said:
Don, I find your posts very intelligible but then I,too, am an engineer. Interesting article. It ignores the KISS principle, though . o_O
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Don, I concur with @Wombat in that I also find your posts very intelligible (and very informative), although not and engineer, I am a scientist (chemist). Please keep your highly relevant comments coming!
 
I had some LANSCHE speakers with plasma tweeters , the speakers weren’t that fantastic and the ( fairly short interval ) servicing was prohibitively expensive!
I did have a couple ups visit who wanted ot hear som Hi-res files as they were both near seventy years of age I am not sure exactly what they expected to hear.
Keith
 
The problem with plasma speakers seems to be the ozone and nitrogen oxides produced.
One option is to use Helium. That is probably the servicing Keith mentioned.

Another solution is ionic wind.
An attempt has been made to use this for speakers: http://www.electrostatics.org/images/esa_2008_a2.pdf
Later they switched to fan less cooling systems.
 
DonH56 said:
Off-topic: Plasma drivers

There have been several "plasma" speakers and tweeters (Ionovac, anyone?) but the one I remember is the Hill Plasmatronics; think it is the only one I actually heard.

https://www.stereophile.com/content/hill-plasmatronics-type-1-loudspeaker

Gotta' love this comment from the review (ca. 1980):

"Considering the current chaotic state of the high-end" audio field, few listeners will get any real idea of what these speakers can and cannot do until digital program sources become more widely available."

I am an engineer so English, albeit my native tongue, is a foreign language... :)
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I have heard a few Acapella and to me, at the time, they sounded good. They are beautiful and stoopidly expensive. Are they worth the price? ... As usual this has come to be one fundamental question in High Fidelity and High End Audio... Are there out speakers of less exotic drivers that are better? I have heard many . Less expensive? Definitely...
Seems that in Audio , it has come that we are into Jewelry territory IOW performance has nothing to do with price .. vide Rolex, Patek Philip or whatever luxury brands you want to name vs Casio or Citizen or Seiko ... Or a JBL LSR 308 vs some usual audio shrine, dare I say, many that would include the famed LS50 (No!! I won't name the brand :D)

And Don, your posts are lucid and informative. Your humility belies your vast knowledge and mastery of many areas of Electronic Design. Thanks for posting
 
Blumlein 88 said:
Just means the technology needs a little more development. Maybe a magnetic containment bottle for the plasma.

I seem to remember one good thing was these plasma speakers were very efficient.

I think the other one in mind was made by a French company. Same issue, they thought they had a way to keep ozone to tolerable levels, but it didn't work well enough.
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No need to use magnetic containment. Just be sure that listeners dress properly before firing up their plasma speakers.

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We and the audiophiles love to point out the practical problems with plasma drivers--that they generate ozone, need to be "recharged," and produce a lot of heat. These practical problems have justifiably caused most of us to view plasma drivers as a nonstarter.

But somehow many of us see the problems with plasma drivers as fundamentally different from the enormous problem with other exotic loudspeaker technologies, such as beryllium tweeters and cone drivers coated with carbon nanotubes. The problem with those technologies, of course, is their obscene cost, which--like the practical problems with plasma drivers--ensures that those other technologies will always be a nonstarter except among a tiny number of the very wealthy.

One could be impressed in certain respects by Magico or Lansche loudspeakers, but, when they cost more than what many single-family homes in the United States cost, one should ask whether these exotic technologies are innovative at all.

Oops, I'm preaching to the choir.
 
First, thanks for the kind words, guys.

Next, most plasma drivers do use helium AFAIK, and the ozone levels generated are very small. That was one of the things Dr. Hill addressed and it has been raised by numerous other designers. They are mostly horn-loaded IIRC and the plasma driver's acoustic output is actually pretty small. That said, I have done essentially *zero* research on plasma drivers in the last decade or three. The cost of helium tanks and recharging once or twice a year is a major PITA for many folk, and heat is definitely an issue for most of the designs. Integrating the plasma driver(s) to bass drivers (essentially required to get enough LF output) is also a major challenge.

One cool thing about plasma drivers is that, as you push the volume to the limits, the gas simply stops expanding and sort of self-limits in a "soft" way. I still remember watching and listening as the Hill speakers were overdriven and noticed how the plasma driver just sort of softened out without getting all harsh or cracking mechanically like cones or panels. Or maybe I've just forgotten after so many years...

There have been a few other very unconventional designs over the years that would be worth a search (not sure when I'll have time -- few other things going on right now). One I recall used ultrasonic vibrations from an array of piezo drivers or some such and a modulator to allow it to "place" the coherent sound at a particular point in space. Out of that spot, you heard some noise/hiss or nothing. Audio beamforming. There was another trying to use a laser to manipulate... something, can't recall what... and create "holographic" sound. I only read about that one, never saw (heard) a demo, and never heard anything else about it. There was a group at one of the research labs toying with the idea of plasma drivers and superconducting containment fields. My contract was on something else but they were piddling in the back room with it and led me through it. The base application was military but they thought the (new then) "high-temperature" superconductors (using liquid nitrogen instead of liquid helium) might make it practical for consumers. Again I never heard any more about it. Ditto ideas for using a plasma "sheet" instead of a sphere, sort of a plasma ESL panel. Containment and alignment/control of the plasma sheet was pretty challenging IIRC.

Now having said I've no time to actually do the work, I think a (maybe just this) thread on these and other very unconventional designs would be interesting. I imagine many folk on ASR have much more and deeper knowledge than I; I really am not a speaker designer, haven't really done any since my DIY servo sub a long, long time ago, and my day job is far removed from audio. For now I get by with my Revels, when I have time to listen!

I suspect a few relevant posts from our Central Scrutinizer (@RayDunzl) are forthcoming... :)
 
1st I want to agree with those who said Don is very lucid and gives great understandable explanations about things I don't really understand. Sometimes his hints have allowed me to understand something I didn't.

Not a plasma, but I remember those speakers that were going to use an ultrasonic carrier to put sound in various locations. Really would have worked like class D amps. Run a ultrasonic carrier and manipulate it to create waves in the area at audible frequencies. I seem to recall a British company called NEXT, but heard no more about them.

I did find this.
http://ultrasonic-audio.com/products/acouspade-directional-speaker/

Runs on a 40 khz carrier frequency (which for hirez hearing audiophiles could never work could it). Be sure and watch the video about how directional it is. And click on the Technical Explanations at the bottom of the page for more on how it works. Would appear to be one way to have effectively no room reflections involved.


Sennheiser Audiobeam was such a speaker too. Apparently no longer available. Another one is called a Soundlazer.

https://www.performanceaudio.com/item/sennheiser-audiobeam/11174/
 
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Think I'll build this piezo tweeter for my next speaker build ...

 
March Audio said:
I dont care what they sound like, the speakers on that site look fantastic. They are art as far as Im concerned :)
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My dad owns a few. They actually sound great , much better than a few high end speakers i've compared with.
 
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